The Song of the Cell: An Exploration of Medicine and the New Human

by Siddhartha Mukherjee

[Life] is a continuing rhythmic movement, of the pulse, of the gait, even of the cells. —Friedrich Nietzsche

A life within a life. An independent living being—a unit—that forms a part of the whole. A living building block contained within the larger living being.

Animals and plants—as seemingly different as living organisms could be. Yet, as both Schwann and Schleiden had noticed, the similarity of their tissues under the microscope was uncanny. Schwann’s hunch had been right. That evening in Berlin, he would later recall, the two friends had converged on a universal and essential scientific truth: both animals and plants had a “common means of formation through cells.”

The second is the transfer of cells from body to body (including back into our own bodies), exemplified by blood transfusions, bone marrow transplantation, and in vitro fertilization (IVF). The third is the use of cells to synthesize a substance—insulin or antibodies—that produces a therapeutic effect on an illness.

And most recently, there is a fourth category: the genetic modification of cells, followed by transplantation, to create cells, organs, and bodies endowed with new properties.

Life’s definition, as it stands now, is akin to a menu. It is not one thing but a series of things, a set of behaviors, a series of processes, not a single property. To be living, an organism must have the capacity to reproduce, to grow, to metabolize, to adapt to stimuli, and to maintain its internal milieu.

In a sense, then, one might define life as having cells, and cells as having life.

What is a cell, anyway? In a narrow sense, a cell is an autonomous living unit that acts as a decoding machine for a gene. Genes provide instructions—code, if you will—to build proteins, the molecules that perform virtually all the work in a cell. Proteins enable biological reactions, coordinate signals within the cell, form its structural elements, and turn genes on and off to regulate a cell’s identity, metabolism, growth, and death. They are the central functionaries in biology, the molecular machines that enable life.I

And finally, a cell is a dividing machine. Molecules within the cell—proteins, again—initiate the process of duplicating the genome. The internal organization of the cell changes. Chromosomes, where the genetic material of a cell is physically located, divide. Cell division is what drives growth, repair, regeneration, and, ultimately, reproduction, among the fundamental, defining features of life.

All living organisms are composed of one or more cells.

The cell is the basic unit of structure and organization in organisms.

All cells come from other cells (Omnis cellula e cellula). Normal physiology is the function of cellular physiology. Disease, the disruption of physiology, is the result of the disrupted physiology of the cell.

These, then, are among the first and most fundamental properties of the cell: autonomy, reproduction, and development.I

Those who have not trained in chemistry or medicine may not realize how difficult the problem of cancer really is. It is almost—not quite, but almost—as hard as finding some agent that will dissolve away the left ear, say, and leave the right ear unharmed. —William Woglom, 1947